1. Technical Field of the Invention
The present invention relates to a distributed transactional processing system, and in particular to a system and method of replicating data in a distributed database.
2. Background and Objects of the Invention
Today, many computing systems, such as distributed transactional processing systems, utilize cache memory in order to increase processing speeds. A cache may typically comprise random access memory (RAM) and a register which points to a location in the RAM where previously stored data resides. Cache memory may be a fraction of the size of main memory. By keeping the most frequently accessed data in the cache, memory access time approaches the access time of the cache.
High performance transactional processing systems typically possess relatively high data transaction rates and data availability characteristics. These required system characteristics have led to the architecture of system databases to both employ cache memory to achieve the high data transaction rates as well as use redundant memory devices to better ensure that data is substantially and consistently accessible to the rest of the system. For example, prior systems have employed a pair of cache memories designated as a primary cache and a secondary cache. Prior systems additionally employed a pair of disk memories designated as a primary disk memory and a secondary disk memory.
One problem associated with systems employing redundant memory devices concerns data replication, i.e., maintaining consistency throughout the memory database during system operation. Prior transactional processing systems included various synchronous protocols to replicate data between the memory devices. One such synchronous protocol, a two phase commit procedure, often causes the database and system to hang in the event access to a memory device fails. As a result, there exists a need for an improved data replication procedure for use in a transactional processing system.
It is an object of the present invention to provide a method for replicating data in a distributed transactional processing system.
It is another object of the present invention to provide such a method which better maintains database availability despite memory device failure.